There is a significant demand for the development of improved occlusion-type devices and/or systems for the treatment and/or amelioration of aneurysms. This observation is supported by the abundance and wide-range of current occlusion devices and/or systems currently in the aneurysm treatment field. However, there still remains an unmet need for providing aneurysm treatment and/or amelioration, particularly for neurovascular aneurysms, via occlusion devices comprised of a minimum amount of fully-retrievable deployable material.
It is well known that an aneurysm forms when a dilated portion of an artery is stretched thin from the pressure of the blood. The weakened part of the artery forms a bulge, or a ballooning area, that risks leak and/or rupture. When a neurovascular aneurysm ruptures, it causes bleeding into the compartment surrounding the brain, the subarachnoid space, causing a subarachnoid hemorrhage. Subarachnoid hemorrhage from a ruptured neurovascular aneurysm can lead to a hemorrhagic stroke, brain damage, and death. Approximately 25 percent of all patients with a neurovascular aneurysm suffer a subarachnoid hemorrhage. Neurovascular aneurysms occur in two to five percent of the population and more commonly in women than men. It is estimated that as many as 18 million people currently living in the United States will develop a neurovascular aneurysm during their lifetime. Annually, the incidence of subarachnoid hemorrhage in the United States exceeds 30,000 people. Ten to fifteen percent of these patients die before reaching the hospital and over 50 percent die within the first thirty days after rupture. Of those who survive, about half suffer some permanent neurological deficit.
Smoking, hypertension, traumatic head injury, alcohol abuse, use of hormonal contraception, family history of brain aneurysms, and other inherited disorders such as Ehlers-Danlos syndrome (EDS), polycystic kidney disease, and Marfan syndrome possibly contribute to neurovascular aneurysms.
Most unruptured aneurysms are asymptomatic. Some people with unruptured aneurysms experience some or all of the following symptoms: peripheral vision deficits, thinking or processing problems, speech complications, perceptual problems, sudden changes in behavior, loss of balance and coordination, decreased concentration, short term memory difficulty, and fatigue. Symptoms of a ruptured neurovascular aneurysm include nausea and vomiting, stiff neck or neck pain, blurred or double vision, pain above and behind the eye, dilated pupils, sensitivity to light, and loss of sensation. Sometimes patients describing “the worst headache of my life” are experiencing one of the symptoms of a ruptured neurovascular aneurysm.
Most aneurysms remain undetected until a rupture occurs. Aneurysms, however, may be discovered during routine medical exams or diagnostic procedures for other health problems. Diagnosis of a ruptured cerebral aneurysm is commonly made by finding signs of subarachnoid hemorrhage on a CT scan (Computerized Tomography). If the CT scan is negative but a ruptured aneurysm is still suspected, a lumbar puncture is performed to detect blood in the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord.
To determine the exact location, size, and shape of an aneurysm, neuroradiologists use either cerebral angiography or tomographic angiography. Cerebral angiography, the traditional method, involves introducing a catheter into an artery (usually in the leg) and steering it through the blood vessels of the body to the artery involved by the aneurysm. A special dye, called a contrast agent, is injected into the patient's artery and its distribution is shown on X-ray projections. This method may not detect some aneurysms due to overlapping structures or spasm.
Computed Tomographic Angiography (CTA) is an alternative to the traditional method and can be performed without the need for arterial catheterization. This test combines a regular CT scan with a contrast dye injected into a vein. Once the dye is injected into a vein, it travels to the brain arteries, and images are created using a CT scan. These images show exactly how blood flows into the brain arteries. New diagnostic modalities promise to supplement both classical and conventional diagnostic studies with less-invasive imaging and possibly provide more accurate 3-dimensional anatomic information relative to aneurismal pathology. Better imaging, combined with the development of improved minimally invasive treatments, will enable physicians to increasingly detect, and treat, more silent aneurysms before problems arise.
Several methods of treating aneurysms have been attempted, with varying degrees of success. For example, open craniotomy is a procedure by which an aneurysm is located, and treated, extravascularly. This type of procedure has significant disadvantages. For example, the patient undergoes a great deal of trauma in the area of the aneurysm by virtue of the fact that the surgeon must sever various tissues in order to reach the aneurysm. In treating cerebral aneurysms extravascularly, for instance, the surgeon must typically remove a portion of the patient's skull, and must also traumatize brain tissue in order to reach the aneurysm. As such, there is a potential for the development of epilepsy in the patients due to the surgery.
Other techniques used in treating aneurysms are performed endovascularly. Such techniques typically involve attempting to form a mass within the sac of the aneurysm. Typically, a microcatheter is used to access the aneurysm. The distal tip of the microcatheter is placed within the sac of the aneurysm, and the microcatheter is used to inject embolic material into the sac of the aneurysm. The embolic material includes, for example, detachable coils or an embolic agent, such as a liquid polymer. The injection of these types of embolic materials suffers from disadvantages, most of which are associated with migration of the embolic material out of the aneurysm into the parent artery. This can cause permanent and irreversible occlusion of the parent artery.
For example, when detachable coils are used to occlude an aneurysm which does not have a well-defined neck region, the detachable coils can migrate out of the sac of the aneurysm and into the parent artery. Further, it is at times difficult to gauge exactly how full the sac of the aneurysm is when detachable coils are deployed. Therefore, there is a risk of overfilling the aneurysm in which case the detachable coils also spill out into the parent artery.
Another disadvantage of detachable coils involves coil compaction over time. After filling the aneurysm, there remains space between the coils. Continued hemodynamic forces from the circulation act to compact the coil mass resulting in a cavity in the aneurysm neck. Thus, the aneurysm can recanalize.
Embolic agent migration is also a problem. For instance, where a liquid polymer is injected into the sac of the aneurysm, it can migrate out of the sac of the aneurysm due to the hemodynamics of the system. This can also lead to irreversible occlusion of the parent vessel.
Techniques have been attempted in order to deal with the disadvantages associated with embolic material migration to the parent vessel. Such techniques are, without limitation, temporary flow arrest and parent vessel occlusion, and typically involve temporarily occluding the parent vessel proximal of the aneurysm, so that no blood flow occurs through the parent vessel, until a thrombotic mass has formed in the sac of the aneurysm. In theory, this helps reduce the tendency of the embolic material to migrate out of the aneurysm sac. However, it has been found that a thrombotic mass can dissolve through normal lysis of blood. Also, in certain cases, it is highly undesirable from a patient's risk/benefit perspective to occlude the parent vessel, even temporarily. Therefore, this technique is, at times, not available as a treatment option. In addition, it is now known that even occluding the parent vessel may not prevent all embolic material migration into the parent vessel.
Another endovascular technique for treating aneurysms involves inserting a detachable balloon into the sac of the aneurysm using a microcatheter. The detachable balloon is then inflated using saline and/or contrast fluid. The balloon is then detached from the microcatheter and left within the sac of the aneurysm in an attempt to fill the sac of the aneurysm. However, detachable balloons also suffer disadvantages and as such this practice has all but been superseded by the current practice of deployment of coils or other types of occlusion devices. For example, detachable balloons, when inflated, typically will not conform to the interior configuration of the aneurysm sac. Instead, the detachable balloon requires the aneurysm sac to conform to the exterior surface of the detachable balloon. Thus, there is an increased risk that the detachable balloon will rupture the sac of the aneurysm. Further, detachable balloons can rupture and migrate out of the aneurysm.
Another endovascular technique for treating aneurysms involves occlusion devices having two expandable lobes and a waist, or an expandable body portion, a neck portion, and a base portion.
Still another endovascular technique for treating aneurysms involves occlusion devices for intrasaccular implantation having a body portion designed to fill and/or expand radially into the space within the sac of the aneurysm.
While such occlusion devices may be found, for example in U.S. Pat. Nos. 5,025,060; 5,928,260; 6,168,622; 6,221,086; 6,334,048; 6,419,686; 6,506,204; 6,605,102; 6,589,256; 6,780,196; 7,044,134; 7,093,527; 7,128,736; 7,152,605; 7,229,461; 7,410,482; 7,597,704; 7,695,488; 8,034,061; 8,142,456; 8,261,648; 8,361,138; 8,430,012; 8,454,633; and 8,523,897; and United States Application Numbers 2003/0195553; 2004/0098027; 2006/0167494; 2007/0288083; 2010/0069948; 2011/0046658; 2012/0283768; 2012/0330341; and 2013/0035712; European Application Number EP 1651117; and International Application Number WO13/109309; none of these references disclose the embodiments of the occlusion device disclosed herein.
Therefore, the present invention provides innovative improvements and several advantages in the field of vascular occlusion devices because the occlusion device disclosed herein provides aneurysm treatment and/or amelioration, particularly for neurovascular aneurysms, via the use of a minimum amount of fully-retrievable deployable material. The configuration of such an oversized occlusion device eliminates the need for additional material for pinning the aneurysm neck and/or for an anchoring mechanism in the parent vessel adjacent to the aneurysm and/or for spherical, radial expansion of the body portion of the device into the sac of the aneurysm.
All documents and references cited herein and in the referenced patent documents, are hereby incorporated herein by reference.